272 THE PRINCIPLES OF Part II. 



from each other in external appearance, it is the male 

 which, with rare exceptions, has been chiefly modified ; 

 for the female still remains more like the young of her 

 own species, and more like the other members of the 

 same group. The cause of this seems to lie in the 

 males of almost all animals having stronger passions 

 than the females. Hence it is the males that fight 

 together and sedulously display their charms before 

 the females ; and those which are victorious transmit 

 their superiority to their male offspring. Why the 

 males do not transmit their characters to both sexes 

 will hereafter be considered. That the males of all 

 mammals eagerly pursue the females is notorious to 

 every one. So it is with birds ; but many male birds 

 do not so much pursue the female, as display their 

 plumage, perform strange antics, and pour forth their 

 song, in her presence. With the few fish which have 

 been observed, the male seems much more eager than 

 the female ; and so it is with alligators, and apparently 

 with Batrachians. Throughout the enormous class of 

 insects, as Kirby remarks, 11 " the law is, that the male 

 " shall seek the female." With spiders and crustaceans, 

 as I hear from two great authorities, Mr. Blackwall and 

 Mr. C. Spence Bate, the males are more active and more 

 erratic in their habits than the females. With insects and 

 crustaceans, when the organs of sense or locomotion are 

 present in the one sex and absent in the other, or when, 

 as is frequently the case, they are more highly developed 

 in the one than the other, it is almost invariably the male, 

 as far as I can discover, which retains such organs, or has 

 them most developed ; and this shews that the male is 

 the more active member in the courtship of the sexes. 12 



11 Kirby and Spence, 'Introduction to Entomology,' vol. iii. 182G, 

 p. 342. 



12 One parasitic Hymenopterous insect ("Westwood, ' Modern Class, 

 of Insects,' vol. ii. p. 160) forms an exception to the rule, as the male 



